Anyone in the USA willing to test their micrometer reading skills?

Let's find out how well CHE can compare with the Oehler Personal Ballistics Laboratory M43.

I'll send you one each of 6 different brands of .223 Remington virgin, factory-fresh empty brass cases; Remington, Winchester, Federal, Lapua, Nosler and Norma. You use whatever instrument you normally use to measure case head expansion. File flats on the head or mark them with a Sharpie or engrave some kind of system so you can measure each case before, and then after, it gets fired in my Remington 700 .223 Remington AI chambered rifle.

You measure them unfired and post the raw measurement in this forum. Send them back to me and I'll load them with primer, a stout load of powder, and a suitable bullet for my 1 in 12" twist barrel. After firing and measurement via strain gauge, I'll then send them back to you to remeasure. Post that data and do the subtraction to find out how much CHE there was--.0004", .0005", or perhaps even more. From that measurement, YOU tell us if the pressure was normal, MAX, or dangerous...that's it, just 3 choices. I'll then post my M43 readings and we can compare just how well the never been bettered CHE (and of course your skill) is at matching Dr. Oehler's invention.

All it will cost you is a bit of your time and a one way USPS Priority Mail trip of a padded envelope.

Who's game? Who's curious?

If someone wishes to modify my procedure, I'm all ears.

Hey Dave, This is an exercise I've tried to get run ever since Stanley Watson(OKShooter) bought a M43 years and years ago. I remember another guy running a Test here at AR, but I never believed "his" data.

However, I have no reason to doubt what you would report and fully support your efforts. I'd be glad to do the CHE/PRE portion "if" no one else steps forward to help you. However, I do believe it would be a better Test if someone else offered to help you. Maybe Kelbro, Woods, Ol` Joe, etc.
-----

1. I'd encourage you to buy a box of Factory Ammo(non-plated) and shoot "9 or 12" of them across your M43 to establish a Benchmark Standard for the Pressure.

2. Average all the data, which I'll guess your M43 does anyhow.

3. Send those Cases to the person assisting you.

4. He can then measure the Case prior to CHE, record that dimension, and Mark the Cases so each one is Uniquely identifiable. I agree that "Filing" a Marker on the Case Head is the way to go.

5. Return them to you along with the Pre-CHE Measurements. This is the number you use to base the next shot Expansion on.

6. Then you need to either Full Length Resize or Partial-Full Length Resize the Cases to fit your rifle. Neck Sizing will invalidate the Test. That was the problem I had when trying to perform this simple Test with Stanley. He could not grasp the concept that the Pressure Ring must be Resized between shots, so PRE is accurate.

7. Fire whatever you want in the Cases. I'd encourage you to do them in 3-shot groups so the CHE/PRE data can be Averaged.

8. Send them to your assistant for the CHE/PRE Measurements.

I've tried to get that done in the past. And as simple as it seems, I've yet to get it accomplished.

Whoever helps you should follow these Instructions on How to Measure CHE & PRE. If they do it any other way, the Test is invalid.

Best of luck to you and whoever assists you in the Test.

I will be glad to participate. I have been reading micrometers on close tolerance applications for decades. I have no conditions but I do have one question.

Have you tried this yourself yet?

I'd be glad to do it if you buy me one of these.



my small fee for my participation.

quote:

Originally posted by SR4759:
I will be glad to participate. I have been reading micrometers on close tolerance applications for decades. I have no conditions but I do have one question.

Have you tried this yourself yet?

SR4759, you've got the job. (PM me you name and address) BUT, the way I envision this exercise, you not only need to accurately measure the cases, but interrupt the results. That is, the .223 Remington has a SAAMI Maximum pressure limit of 55K psi. If the difference in your precise, never fail, can't be equaled measurement before firing, and then after firing was, say, .0005" would you determine that to be normal, MAX, or dangerous pressure (psia)?

I will say this once again, "No, I have not\cannot try this experiment because I never found a $25 pawn shop thin blade micrometer that was .0001" capable. I invested in a strain gauge device...when it reads 55K psi (M43), I know that's max and I quit adding powder or even shoot in a much higher ambient temperature.

But this is not so much about the strain gauge's operation as it is satisfying my curiosity about the average reloader performing this CHE protocol and coming out with useful information. Just measuring and writing down a 4 decimal-to-the-right-of-zero number isn't telling you anything until you can afix a nominal pressure value to your result.
I got frustrated with the tedious measuring of a belted case using a flat anvil mic. CHE, and by extension, PRE are just not my forte.

So SR4759, you tell me how we should set up this experiment so you have the best chance of being correct?

Hotcore, do you have an issue with me proposing to fire a factory spec .223 Remington cartridge in a 40 degree improved chamber? Are you saying the case head swelling would be somehow compromised from accurate measurement? That your mechanical handtool or my strain gauge would not record the actual pressure generated by the burning gunpowder?

I have 5 Federal Premium #P223E 55gr Sierra Gameking BTHP factory loads. Good enough to get a baseline?

I assure everyone, this is no game or joke or fantasy. I DO NOT intend to load squib loads. This is not some kind of troll GOTCHA! Lets see how easy it is, by using CHE, to determine when the 55K psi limit is reached. It's that simple.

quote:

you tell me how we should set up this experiment so you have the best chance of being correct?

Your criteria is good, bad and ugly.

If you do not have a means to correlate your pressure results to case head expansion you have to make assumptions.
My assumptions would be .0000 expansion Good
.0003 expansion Bad
more expansion Ugly

This is based on the dinky case head diameter of the .223 case.

I have the micrometer that Woods pasted but I do not consider brass uniform enough from one case to another to think that results of such a small sample will mean a lot.

If you want meaningful results the sample size need to be statistically significant.

My view of case head expansion is none is safe.
Any detectable case head is suspect. If the same load is repeatedly fired in the same case and it continues expanding it is not acceptable.
The only way to determine a maximum usable load is to shoot enough to prove it is safe.

The 5 factory loads that you have are safe in a normal chamber. They would develop less pressure in your AI chamber. You can fire them and get a pressure to start.

The other side of the question is what pressures out of your strain gauge do you consider as normal, maximum and excessive?

I would be glad to participate but I do not think that your test plan is structured according to HC's methodology nor is your sample size adequate to draw any real conclusions between CHE and strain-gauge measurements.

I agree with SR4759 that .0001 or better is not good.

Might be easier to take the CHE measurements first, then run a few at 55-56K and then take more measurements. If there is any CHE, that measurement would tell the limit for that lot of brass.

quote:

Originally posted by onefunzr2:
...Hotcore, do you have an issue with me proposing to fire a factory spec .223 Remington cartridge in a 40 degree improved chamber?

Hey Dave, Your AI Chamber will skew the results of the Factory Ammo to a "lower than normal" Benchmark Standard, or "less Pressure" as SR4759 mentioned. But as I'm sitting here thinking about it, perhaps it would be easy enough to do Two Tests. If you have another rifle Chambered for a Standard Cartridge, then firing the Factory Ammo would have a better chance of creating your Benchmark Standard at a level that looks normal. Perhaps one AI and one Standard Chamber.

SR4759 mentioned using 5-Cases, which would all get the same Load, and that would be excellent too. It would help with the Averaging and reduce the number of Marks on the Case Head, which is good on both counts. And if you decide to go with the two Cartridges, it would only be 10-Cases in total.

quote:

Are you saying the case head swelling would be somehow compromised from accurate measurement?

No, the CHE will still work with an AI Chamber. As far as I know, it is the only thing besides Primer Pocket Expansion that does work with an AI Chamber. But the AI Chamber will show a Reduced PRE with Factory Ammo, just as it will show a Reduced Pressure on your M43.

quote:

That your mechanical handtool or my strain gauge would not record the actual pressure generated by the burning gunpowder? ...

CHE will measure the first-hand, direct effects of the Pressure - if - the Pressure is High enough to begin changing the Case. PRE will measure much Lower Pressure Effects, just as the Strain Gauges will. The difference is PRE provides First-Hand Pressure Data, where the Strain Gauge System provides 3rd Hand, Mathmatical Model, Massaged, Pressure Data.
-----

4a. If SR4759 has a Universal Decapper(or if you do), it might be interesting to push out the Spent Primer, Square(Ream) the Primer Pocket, Deburr the Flash Hole, Trim, Champfer, Deburr and then Weigh each Case, prior to the Resizing. I'm thinking the M43 might be sensitive enough to detect changes in Case Weights, as that relates to Internal Volume, which would slightly change the Pressure. Then again, that speculation might be Full-of-Beans.

I've seen some good discussions on whether or not variance in Case Weight makes a difference in regards to Internal Volume. Some think it does make a difference and some do not. I would think as long as the Cases are all from the same Lot, the odds of the Case Weight changing the Internal Volume stand a good chance. Your Test "might" also answer that question.
-----

4b. I'd also include Groove Expansion(GE). The person doing the Measuring can use the same Marker on the Case Head to Index this measurement to the same spot. I use the center letter in WIN, FED or REM because they contain a straight line. But the person doing the CHE and GE should use whatever they like, as long as it is repeatable.
-----

I'd encourage everyone reading this to "Think" and see if there is anything else that could be included that would answer more questions we have all had from time to time. Going to 5-shots helps a lot and was an excellent idea.
-----

Hey Dave, With a bit of luck, this Test "might" indicate the 3rd Hand Massaged Data from M43 is actually worth something.
-----

Hey Woods, I can't believe "you of ALL people" would pass up the opportunity to buy a Tool. I realize a Precision Instrument is not a Thingy, and provides useful accurate info. But it really would not hurt you to have one Measurement Tool which provides you with "useful" information.
-----

A sincere THANK YOU to Dave for getting this Test coordinated. It is about time we had someone run it that will provide Data we can actually Trust. Same for SR4759.

I am PLEASANTLY shocked at all the apparant co--operation. roger

quote:

Originally posted by SR4759:

quote:

you tell me how we should set up this experiment so you have the best chance of being correct?

Your criteria is good, bad and ugly.

If you do not have a means to correlate your pressure results to case head expansion you have to make assumptions.
My assumptions would be .0000 expansion Good
.0003 expansion Bad
more expansion Ugly

This is based on the dinky case head diameter of the .223 case.

Hotcore, I'm surprised you have not commented on the above.

For future reference, please list the ~pressure associated with CHE of a .223 brass case @

.0001" expansion
.0002"
.0003"
.0004"
.0005"
.0006"

BTW, no one has PM'ed me their contact info yet.

Think I will bow out of this.

And we haven't even gotten the ground rules in place yet. Oh my!

BTW Hotcore, I do have a H&R SB2 chambered in .223 Remington. It doesn't yet have a strain gauge over its chamber but I have no constraint not to. Except my lot of special superglue is way past its use-by date. Although it still sticks my fingers together quite well!

quote:

Originally posted by onefunzr2:

quote:

Originally posted by SR4759:

quote:

you tell me how we should set up this experiment so you have the best chance of being correct?

Your criteria is good, bad and ugly.

If you do not have a means to correlate your pressure results to case head expansion you have to make assumptions.
My assumptions would be .0000 expansion Good
.0003 expansion Bad
more expansion Ugly

This is based on the dinky case head diameter of the .223 case.

Hotcore, I'm surprised you have not commented on the above.

Hey Dave, That is as good a starting point as any. It depends on how the Primer Pocket responds to the Pressure required to create that amount of Expansion.

quote:

For future reference, please list the ~pressure associated with CHE of a .223 brass case @

.0001" expansion
.0002"
.0003"
.0004"
.0005"
.0006"

BTW, no one has PM'ed me their contact info yet.

CHE & PRE do not give specific amounts of Pressure in psi. No one has ever claimed they do, because they do not.

Let me suggest that you read the Link to the Instructions on how to measure CHE & PRE. These types of questions should be covered in there.
-----

What happened SR4759?
-----

Hey Dave, I'll be glad to send you a PM with contact info. I love my 223Rem, but I do not have a "Small" Primer Pocket Reamer, only have a Large one.

That was the only reason for me to suggest a different size Cartridge. We can just skip Reaming the 223Rem Primer Pockets and do all the rest.
-----

quote:

Whammed in by Bartsche:
I am PLEASANTLY shocked at all the apparant co--operation.

Hey Bartsche, I'm sure you know that we do not all have to agree 100% on everything to be able to discuss issues. Being the totally amiable guy that I am, helps though.
-----

Hey Kelbro, If you want to jump in for SR4759, it is fine with me. Otherwise, I'll do the Test with Dave.

I've talked "a bit" about CHE & PRE in the past(Dave might claim a bit more than "a bit" ) and I think folks would be more likely to believe the results from someone who has not used CHE & PRE as long as I have.
-----

Hey Dave, PM will be on the way in a couple of minutes.

I'm game. PM'd you my contact info.

As a relative newby at the CHE/PRE stuff but with plenty of years of experience reading precision measuring equipment, I'll be your huckleberry.

Especially interested since I have two 223AIs that behave quite differently than standard 223s.

Hey Kelbro, I've no problem with bof'us(both of us for the YANKEES) doing the Measuring and seeing how close we come to each other. It would only delay getting the Cases back to Dave for a couple more days.

I'll send you my contact info too, just in case we want to do it.
------

I left a Voice Mail for our esteeeeemed Mr. Woods. Haven't heard a thing back from him. Perhaps all the HEAT they had to endure has melted him down a bit.
------

Anybody else got some ideas on additional things we need to be Testing while we are in to it?

We could run them past Larry and see how much Doughnut-Dust affects the Measurements!
-----

Raining here today. It would be a good day to do some Case Measuring. Meanwhile, I'll try to come up with a Data Sheet for the Measurement Values.

Hey Dave, Does the M43 software accept Data from Excel?

quote:

Originally posted by Hot Core:

CHE & PRE do not give specific amounts of Pressure in psi. No one has ever claimed they do, because they do not.[/QUOTE]

If not specific pressure than generalized pressure. After all, how are we to make comparisons? My system yields data in units of pounds of pressure per square inch...which, I believe, is a universal unit of measure.
Isn't there some sort of tarage table that equates case head swelling with pressure? How can we pursue this experiment if CHE doesn't produce a quantifiable unit of measure?

M43 does not allow Excel data entry, to my knowledge. It has imputs from a strain gauge, an acoustic target or 2 three detector skyscreens. That's it. Output, of course, is to a PC.

The limiting component in high-performance reloading is the brass case, thus a reliable measure of impending case failure is valuable. I’ve always looked for the standard indicators of such impending failure such as ejector port impressions, ejector marks, and premature primer pocket loosening. I also chronograph all my shots so I can directly measure excessive velocity. These measures have served me well, but a more precise measure, such as CHE might have value, especially if I can get immediate feedback from it at the range.

The M43 Oehler system is additional expense and hassle. Moreover, I’ve never been convinced there’s a reliable way to test it or calibrate it to guarantee accuracy. In any event, it’ll give me an estimated PSI, which I may or may not find useful, because impending case failure is what I’m most interested in knowing. I’m not paranoid about my guns blowing up, because brass cases will fail long before my guns will fail – brass cases begin to show signs of excessive brass flow at ~65,000 PSI, whereas the bolt actions guns I use are designed to withstand PSIs in excess of 150,000 PSI. If one is going to get involved in high-performance reloading, one should first have first-rate equipment, including first-rate bolt-action rifles.

I this hard to understand, or am I missing something?

Regards, AIU

quote:

Originally posted by onefunzr2:
If not specific pressure than generalized pressure. After all, how are we to make comparisons?

Hey Dave, AIU has done an excellent job of describing "Why" CHE is a big help - it lets you know when the Case is beginning to "Change"(become deformed, reach a semi-plastic state, begin reshaping itself, see the Primer Pocket and Case Head Expanding) which the M43 can not do. That is not meant as Mean Spirited, just a fact that the M43 can't do that.

The M43 can provide information similar to what PRE will indicate though. Once you establish a Benchmark Pressure with Factory Ammo, you can watch the "psi" increase on Hand Loads until you reach the same psi as the Factory Loads and know you are Safe.

PRE will do the same thing by comparing the Average PRE of Factory Ammo with the PRE of Hand Loads in the same Cases. As you start low and increase the Pressure, the PRE also increases and you STOP when you reach the same PRE as the Factory Ammo Benchmark Standard.

Using PRE and CHE together allows the user to see the PRE increasing and gives the user an indication when the CHE will begin to Expand.

It is real simple, comparatively inexpensive and works very well.

quote:

My system yields data in units of pounds of pressure per square inch...which, I believe, is a universal unit of measure.

Yes it does and it is a Measurement that can be "related to".

quote:

Isn't there some sort of tarage table that equates case head swelling with pressure?

No, because the amount of Pressure required to Expand the Primer Pocket, or Case Head is dependant on the "Temper" of the Case Head. You have probably noticed some of your Cases - from different Lots - get Loose Primer Pockets at separate Load Levels than a different Lot of Cases. If you decide to just load to a specific "psi"(Example: 57Kpsi), then some Lots of Cases "might" have Loose Primer Pockets when other Lots will still be snug. The M43 has no way of telling you what is happening to the Case, but CHE does.

quote:

How can we pursue this experiment if CHE doesn't produce a quantifiable unit of measure?

Just for fun? By measuring CHE, the person doing the measuring can tell you if the Primer Pocket is loosening. And by watching PRE, the person doing the measuring can tell you if your Hand Loads have Less, the Same, or More Pressure than the Factory Ammo.

But neither CHE nor PRE tells you what the Pressure is in "psi". They do give you important information about how the Case is responding to the Pressure though.

That is why CHE is real nice for Wildcats, it allows you to see what is happening to the "Weakest Link" in the Firing process, as it is happening. You do not have to load 3-5, shoot, go home and see if the Primer Pockets are still snug before increasing the Load. Same with Factory Cartridges, except now PRE comes in to play and it allows you to see the Pressure "increasing" before CHE begins growing.
-----

I mentioned the Test to a buddy in Califoney and told him how nice the Acoustic Targets were printing your groups. He said he "had heard" they were not real accurate, which threw me. Have you compared a Paper Target behind the Acoustic Target to see how well they match?

My cousin, an engineer at Mitutoyo, shot a bobcat on Sunday with a Winchester Model 94 32W.S.
It was dragging off one of his Rhode Island Red hens.


Is the finish line to this contest, "Who can find the highest velocity with long brass life?"
I think I can get 4100 fps in 223 with long case life.
55kpsi is a red herring.

quote:

Originally posted by Hot Core:
By measuring CHE, the person doing the measuring can tell you if the Primer Pocket is loosening. And by watching PRE, the person doing the measuring can tell you if your Hand Loads have Less, the Same, or More Pressure than the Factory Ammo.

All right. Bottom line. I'm not about to post those 5 factory Federal rounds nor spend the $$$ using UPS with ORM-D sticker. If I priority mail those fired cases and the 6 brand new empty cases, can this experiment be completed with 2 back-and-forth mailings for me, and one for whomever else wishes to participate?

Hey Dave, No need to use the Expensive Mail, regular old Lowest Rate Possible will do fine.

No need to send "unfired cases".

To get started:
1. Fire 5 new Factory Cartridges in your 223AI.
2. Mark " 1 " on the Case Head with a Marks-A-Lot or any marker, then put a piece of Scotch or Transparent Tape over the " 1 " to protect it during Mailing.
3. Include the M43 psi data for each shot with reference to the specific Case.
4. Repeat 1.<->3. for your H&R 223Rem.
5. Mail them to me.

I'll permantely mark the Case Heads, do all the initial measurements, do a Case Prep, Weigh the Cases and record the measurements and weights along with your M43 psi Data for each Cartridge.

Kelbro is out of town, but there is no hurry and I can send all the stuff on to him to see what measurements he gets, once he returns. Then Kelbro can send them to you.

Once you get them back,
A. You will need to either Full Length Resize or Partial-Full Length Resize. Dosen't matter which one you choose as long as the Pressure Ring is re-aligned. Neck Sizing during the Test won't do that.
B. Put whatever Load you desire in them, and load them up. We do need "the same Load" in each of the 10 Cases so I can Average the results and also see the difference between the 223RemAI and the regular 223Rem.
C. Shoot them in the respective rifles again and record the M43 psi in accordance with the number on the Case Head and the Load used.
D. Send them back to me, with the new psi data, by the Slowest(Least Expensive) Mail Possible again.

I'll see what the GE and CHE tells us as well as the PRE. Then off to Kelbro for a second measuring and back to you.
-----

I've got no idea what we will accomplish, but that is why I've been wanting to find someone "I could trust" to do this with for MANY MANY years.

If you decide that you want to do a Load Increment Test, where we see what varying the Load does, we can do that later on.

I sure appreciate your offering to do this.
-----

Hey tnekkcc, Have you ever tried this? If so, how well did the psi values track with your Groove Expansion?

Bytheway, thanks for the Flicks of the Bullet operation.

quote:

Originally posted by Hot Core:

3. Include the M43 psi data for each shot with reference to the specific Case.

I sure appreciate your offering to do this.

What? Is that how you're used to taking tests? With the answers already in front of you?

Why do you need my data to make your own conclusions from your own style of measuring case head expansion?

Ken Waters didn't need it in 1982 when his methods for judging pressure were published in Pet Loads. And quickly perusing that article, Ken says, "...I measure the diameters to which their cases have expanded at the pressure ring, the location of which is obvious." He goes on to say, "Someone is sure to ask why I take measurements over the pressure ring rather than across the solid web of the base. There are at least 4 good reasons for my preferring to use the pressure ring..." So it seems he doesn't use CHE at all. Hmmm, imagine that!

Actually, Mr. Waters used both CHE & PRE. Same as Bob Hagel and Gary Sitton. You can see it in their Books and Articles.

quote:

Originally posted by onefunzr2:
...What? Is that how you're used to taking tests? With the answers already in front of you?

Why do you need my data to make your own conclusions from your own style of measuring case head expansion?...

Hey Dave, I don't need it. I was just going to Average everything and include it on one Chart. You seem to be implying the data you will get from the M43 is without error, perfect, the Gold Standard of data. It would be impossible for me to care less about what your, or anyone else's M43 or anyone's Pressure Trace spews forth.

Surely you are not suggesting that both Kelbro and I would intentionally skew any of the Measurements. You can always check the Measurements yourself before sending the Cases and re-check them after you get them back if you want to know something significant about the Pressure.

Send the Cases without the M43 data.
-----

I've received some PMs and emails that believe Dave is not sincere in trying to run the Test. So everyone is totally clear, I'll continue to go by the never improved upon, always reliable, completely repeatable, good old CHE & PRE regardless of whatever the non-calibrated, guessed at dimensions, fudge factored input, Strain Gauges that provide 3rd Hand Information to the Math Model Software of the M43 provide in this exercise. As far as I am concerned, the Test is seeing how close the M43 with all it's problems (outside a Lab) come to reality.

I'm ready for the once-shot Factory Ammo Cases.
-----

Find Key: findchem43test

Who's going to be the refiree?

The one who gives a


Or runs the flag up

Hey guys! I am really, really interstd in the outcome - not to see who might be right or wrong but to see just how well these two methods correlate. Not for one moment do I believe Hot Core or anyone would skew the findings. This is in the name of 'science'- Mythbuster style! And fun. Hey onefunzr2, I have no reason to think your M43 results are going to be challenged! Sorry Hot Core (Did I mention 'fun'? )

Same here. I was hoping to be able to correlate the CHE/PRE measurements with the M43 measurements. Nothing to do with predicting any pressures based on CHE/PRE alone.

As stated earlier, I started down this path due to the lack of data available for my 223AIs. It's purely educational to me since I have no axe to grind and don't plan to buy an M43. After our experiment, I can draw on chrono readings + CHE/PRE + M43. I likes mo' data!

I know there are some strong opinions bantied about on this site but isn't it really about fellow handloaders helping each other????

HC, I'm heading back to the US of A this weekend. I'll be ready when you finish.

quote:

As far as I am concerned, the Test is seeing how close the M43 with all it's problems (outside a Lab) come to reality.

Hotcore, et al. Scroll up to the very first post. There you will read what I envisioned this test to accomplish: just how reliable, repeatable and accurate CHE is for the average AR handloader member to master. I use Snap-On hand tools every day and yet I couldn't seem to get the hang of measuring a round brass case to the tiny, tiny parts of an inch required to make CHE worth while.

I have no trouble measuring a crankshaft journal to within .001" Or using a .001" capable dial indicator to measure case\bullet runout. But this CHE measuring is smaller by an order of magnitude. I decided I couldn't trust my results. So I posted this little trial to help me decide if I was the only one having the same difficulty.

So you see Hotcore, this trial is all about what I hope to accomplish. We'll do a test some other time with multiple rifles and averaged results to address your needs. I'm not opposed to doing so.

Me cheat? What would I have to gain even if I could? There's a time stamp on every M43 output page that cannot be altered by the user. Every variable, such as barrel length and powder charge, atmospheric pressure, is right there in the open for everyone to see. Once I press the trigger and the M43 spits out its report, it's locked in. If I was to omit one or more less than favorable shot records, a big red flag pops up to show that I did so. And it cannot be hidden. Dr. Oehler built it that way.

If there's anyone with an agenda in this matter, it's YOU.

quote:

I'll continue to go by the never improved upon, always reliable, completely repeatable, good old CHE & PRE regardless of whatever the non-calibrated, guessed at dimensions, fudge factored input, Strain Gauges that provide 3rd Hand Information to the Math Model Software of the M43 provide in this exercise.

And that's why I would rather other AR members provide their input to actually see if CHE does indeed provide 'always reliable, completely repeatable' info.

I've given freely of my reloading experience for almost 7 years here on AR. I thought for once some other members could give me a hand. Any offers? If so, PM me.

quote:

Originally posted by Hot Core:
...I mentioned the Test to a buddy in Califoney and told him how nice the Acoustic Targets were printing your groups. He said he "had heard" they were not real accurate, which threw me. Have you compared a Paper Target behind the Acoustic Target to see how well they match?

And no response.
-----

Getting all kinds of emails a a couple of PMs that think Dave is Shining me about doing the CHE vs. M43 Test. They seem to think he never intended to run the Test and got tripped up when I told him I'd do it. I've been defending him, but it does seem they may be correct.

I have a couple of ways figured out to get around it though. One involves a buddy who has wasted his money on a Pressure Trace System. His family is also having some health problems and I don't know if he has "time" to do it right now or not. I'll call him and see if he would be interested, which I'll guess he might be.

Probably best for me to start a new thread for some actual CHE & PRE Data, just in case Dave comes through and sends the Cases.
-----

Hey Kelbro, Watch for the other thread. Maybe we can do it there.
-----

Edit In: Looks like the PMs and emails were correct.

quote:

Originally posted by Hot Core:
However, I have no reason to doubt what you would report and fully support your efforts. I'd be glad to do the CHE/PRE portion "if" no one else steps forward to help you. However, I do believe it would be a better Test if someone else offered to help you. Maybe Kelbro, Woods, Ol` Joe, etc.

Best of luck to you and whoever assists you in the Test.

I couldn't agree more.

Here's a pic of the actual target that goes with my laptop M43 acoustic target. The 'X' in amongst the bullet holes on the acoustic target is the M43 mark for the group center. The green bullet hole is highlighted to reference that it was the first shot. In practice, I can highlight any one of the shots but can't show it in a static pic. Shot #1 is the default. In case anyone was curious.




Like Fox News...I report, you decide.

Where is the PSI?

I have not yet attached a strain gauge to this Blaser R-93 barrel. It is quite new to me...~20 rounds through the tube so far. I may never attach one.

quote:

Originally posted by onefunzr2:
I have not yet attached a strain gauge to this Blaser R-93 barrel. It is quite new to me...~20 rounds through the tube so far. I may never attach one.

I couldn't agree more.

Sure looks like the Acoustic Target tracks with the actual Bullet Holes to me. Appreciate the Fox news report.

quote:

Originally posted by onefunzr2:

quote:

Originally posted by Hot Core:

3. Include the M43 psi data for each shot with reference to the specific Case.

I sure appreciate your offering to do this.

What? Is that how you're used to taking tests? With the answers already in front of you?

If you think that a strain gauge glued to a tapered barrel will yield accurate absolute measurements, you need to hear about something called "math".

This new "math" stuff is really neat.
Here is how it works:
You calculate the error in the strain gauge placement.
You estimate the error in your formula for stress strain because your barrel in not in Roark's book Formulas for Stress and Strain in open tubes.

Whoops!
You blew your error budget!

Isn't this new "math" stuff fun?

What does it all mean?
If you can't show me the math and measurement traceability to NIST, your absolute measurement has no meaning.

What does THAT mean?
When you make an absolute measurement, it must be accompanies with a tolerance. Like "one inch plus or minus one thousand of an inch".

Things to do:
Visit a calibration lab, where technicians are calibrating test equipment.
Ask them to show you examples of "tolerance", "accuracy", "traceability to NIST".
The supervisor of the lab may have heard of this new "math" stuff. If not, he probably knows where there is an engineer in the same building that understands all this new "math" stuff and what it has to to with measuring.
Should you get a chance to speak with a real engineer, ask him how much work it would be to validate and verify a rifle strain gauge measurement. He may use buzz words to describe variables in the calculation of the accuracy of your process like "out of control".

Hot Core is a really good engineer. Ask him.

quote:

Originally posted by tnekkcc:
If you think that a strain gauge glued to a tapered barrel will yield accurate absolute measurements, you need to hear about something called "math".

Thing is, I don't think the M43 measures in absolutes. I've known it for 12 years. Dr. Oehler points that out in the M43 instruction manual. Where did you get the idea that the data created by the M43 was an absolute value?

I suppose I could spew drivel like that too. Look here, this is the newest way to measure CHE:

quote:

Originally posted by onefunzr2:
Where did you get the idea that the data created by the M43 was an absolute value?

Someone referred to M43 data as "the answers".

quote:

Originally posted by tnekkcc:

quote:

Originally posted by onefunzr2:
Where did you get the idea that the data created by the M43 was an absolute value?

Someone referred to M43 data as "the answers".

I doubt that 'someone' was an actual M43 owner. Please provide a linky to back up your statement.

To get absolute, psia data, you'll need to PM Dr. Ken Oehler. He is an AR member, you know? I'm sure he will be glad to sell you one of his industrial pressure testing units. I think they might be the M82 or M83 models.

Although Dave Scovill, editor of Handloader and Rifle magazines, sent some of his 338 Scovill wildcat ammo to Barnes Bullets to be pressure tested by their ballistics lab. Son-of-a-gun if they didn't use an M43 to get the data. Which seemed to be good enough for him. Read all about it in Rifle, issue #177 beginning on pg 4. It's got a side-by-side comparison with CHE measurements. Which 'someone' said didn't exist.

Dave,
the "linky" would be to your post above.

I have crossed swords here with Oehler in the past about his products.

This is Saeed's site, and he does not like it when I dump on Oehler.

Send some topics to Rifle or handloader magazines and see which ones they are interested in publishing. They are not interested in advancing new science, but reaching out to beginners.


Here is a poem:

quote:

The 'Popular' View of the Gunzine Game… some doggerel from Clark Magnuson:


Those that write the gun rag pages
Make it up, but pose as sages
Those who think that it's all true
Pay the bills to print more poo

Even worse are the reviews
Pay for adds is pay'n dues
If per chance you didn't pay
It ain't so good what we will say

quote:

Originally posted by tnekkcc:
This is Saeed's site, and he does not like it when I dump on Oehler.

Yes, Saeed does own an M43.
So you've got some sort of axe to grind, and you're dumping on me instead? You and Hotcore seem to have the same affliction.

Unless you've got something constructive to contribute, I'd appreciate it if you'd PM Dr. Oehler directly.
Better yet, here's his phone number: (512) 327-6900. He can get downright chatty at times. If you've got something useful to say.

I'm trying to keep the focus of this thread on my quest to correlate CHE to my M43 data. Help me; please don't hinder me. Start your own thread.

I must confess I am rather eager to see some comparisons/correlations! (If I could rush out and buy the equipment and run the test myself, I would. But, ...... I can't, so .... I await in eagerness! )

quote:

Originally posted by onefunzr2:
You and Hotcore seem to have the same affliction.

We have the sensitivity to and remedy for strain gauge posts with erroneous assumptions from Denton Bramwell on this forum.
I have designed and built a better strain gauge amplifier than Oehler's as could Hot Core if he wanted.
We just know too much to keep quiet.

quote:

Originally posted by onefunzr2:


I'm trying to keep the focus of this thread on my quest to correlate CHE to my M43 data. Help me; please don't hinder me. Start your own thread.

Good luck on the correlation, but if you or Denton make any mistakes, I feel compelled to point them out.